Although it might fall somewhat outside their scope, we plan to consult
with the W3C's internationalization working group in any case, so we could
raise the question of checkpoint 4.1 with them on that occasion. I agree
it should be clear which requirements/advice are relative only to a
certain class of languages and which apply more generally. Perhaps one
solution would be to state the assumptions specifically in the techniques,
e.g., if the natural language of the content allows for certain types of
grammatical constructs and these are relatively uncommon by comparison
with certain other constructs then the latter should be used in preference
to the former, where of course we would fill in the details as to exactly
which constructs are under discussion.
On the separate, but related, question of what goes in the advice section
as opposed to the success criteria, it is important to recall the
principles which the working group has agreed on, namely that success
criteria must be machine/HIR testable: it must be determinately true or
not true whether each success criterion is satisfied. Advisory items (in
the "additional ideas") section are, by definition, not testable in this
fashion, but ought to be taken into account in conducting a qualitative
review of the content. So much has been agreed upon already. I think there
is a dangerous temptation to conflate "advisory" with "low priority", and
for people to argue that such-and-such an item should be "advisory", when
what they really mean is that it should occupy the third conformance
level.
Let's keep considerations of testability separate from questions of
conformance level. I am not accusing anybody in this discussion of
confusing the two, just suggesting that there is a very real risk of doing
so.